SI-3000KM series

Surface Molding Series Regulator IC

SI-3000KM series

Jun 2015 Rev.2.0

SANKEN ELECTRIC CO., LTD.

Application Note

Not Reco

mmended

for N

ew D

esign

s:

SI-302

5KM

, SI-3

050K

M

SI-3000KM

2

－－－ Contents －－－

1. General Description

1-1 Features －－－－－－－－－－ 3

1-2 Application －－－－－－－－－－ 3

1-3 Type －－－－－－－－－－ 3

2. Specification

2-1 Package Information －－－－－－－－－－ 4

2-2 Ratings －－－－－－－－－－ 5

2-3 Circuit Diagram －－－－－－－－－－ 10

3. Operational Description

3-1 Voltage Control －－－－－－－－－－ 12

3-2 Overcurrent Protection －－－－－－－－－－ 12

3-3 Thermal Shutdown －－－－－－－－－－ 13

4. Cautions

4-1 External Components －－－－－－－－－－ 14

4-2 Pattern Design Notes －－－－－－－－－－ 15

5. Applications

5-1 Output ON / OFF Control －－－－－－－－－－ 16

5-2 Thermal Design －－－－－－－－－－ 16

6. Typical Characteristics

6-1 SI-3012KM －－－－－－－－－－ 18

6-2 SI-3010KM －－－－－－－－－－ 20

Not Reco

mmended

for N

ew D

esign

s:

SI-302

5KM

, SI-3

050K

M

SI-3000KM

3

The SI-3000KM is a series regulator IC using a hyposaturation type PNP bipolar transistor in the power

section and it can be used with the low difference of input/output voltages. It is provided with an ON / OFF

terminal which operates in Active High mode and the current consumption of circuits at OFF time is zero.

● 1-1 Features - Output current 1A

Output current is 1A at maximum with the outline of TO-252-5L.

- Hyposaturation (Vdif = 0.6 Vmax / Io = 1A)

It can be designed with low difference of input/output voltages.

- ON/OFF function

The ON/OFF terminal which can be directly controlled by TLL logic signals is provided.

- Low current consumption

Current consumption of circuits at OFF time is zero.

Quiescent Current at no load is 600μA at maximum.

- High ripple attenuation ratio

75dB: F = 100 - 120kHz at Vo = 5V

- Built-in Overcurrent protection / Thermal shutdown

The automatic restoration and Foldback type overcurrent protection and Thermal shutdown

circuit are built in.

● 1-2 Application For on-board local power supplies, power supplies for OA equipment, stabilization of secondary output

voltage of regulator and power supply for communication equipment

● 1-3 Type - Type: Semiconductor integrated circuits (monolithic IC)

- Structure: Resin molding type (transfer molding)

1. General Description

Not Reco

mmended

for N

ew D

esign

s:

SI-302

5KM

, SI-3

050K

M

SI-3000KM

4

● 2-1 Package Information

Pin assignment

１． Vc

２． VIN

３． GND

４． Vout

５． Sense（or ADJ terminal for SI-3010KM/SI-3012KM）

2. Specification

Unit: mm

Product mass: about 0.33 g

Marking Method

*1:Product Name

*2:Logo Mark

*3:Lot Number

1st letter：The last digit of year

2nd letter：Month

1 to 9 for Jan. to Sept.,O for Oct.

N for Nov. D for Dec.

3rd letter：day

1 to 9day： for ”1”to “9”

10 to 31day：for “A” to”Z”

(But,“ B”,”I”,”O”,”Q” is removed.

*4:Administer number (Seven

digit)

３＊＊＊ＫＭ

ＳＫ

*2 *3

*4

１ ２ ３ ４ ５

*1

The stem part has same potential as No. 3 pin (GND).

Not Reco

mmended

for N

ew D

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s:

SI-302

5KM

, SI-3

050K

M

SI-3000KM

5

● 2-2 Ratings

2-2-1 Absolute Maximum Ratings Ta = 25°C

Parameter Symbol

Ratings

Units SI-3012KM/3025KM

/3033KM

SI-3010KM/2050KM

/3090KM/3120KM

DC Input Voltage VIN 17 35*1 V

Output Control Terminal

Voltage VC VIN V

DC Output Current Io 1.0 A

Power Dissipation PD*2 1 W

Junction Temperature Tj -30 ro +125 ℃

Storage Temperature Tstg -30 to +125 ℃

Thermal Resistance

(Junction to Air) θj-a 95 ℃/W

Thermal Resistance

(Junction to Case) θj-c 6 ℃/W

*1: A built-in input-overvoltage-protection circuit shuts down the output voltage at the Input Overvoltage

Shutdown Voltage of the electrical characteristics.

*2: When mounted on glass-epoxy board of 900mm2 (copper laminate area 4.3%).

2-2-2 Recommended Conditions

Parameter Symbol Ratings

Units SI-3012KM SI-3025KM SI-3033KM SI-3010KM SI-3050KM SI-3090KM SI-3120KM

Input

Voltage VIN

2.4*2 to

6.0*1

2.4*2 to

5.0*1

*2 to 6.0*1 2.4*2 to

27*1

2.4*2 to

17*1

*2 to 20*1 *2 to 25*1 V

Output

Current Io 0 to 1.0 A

Operational

Ambient

Temperature

Top -30 to 85 ℃

Junction

Temperature

in

Operation

Tj -20 to 100 ℃

*1: VIN (max) and Io (max) are restricted by the relationship PD (max) = (VIN – Vo) × Io .

*2: Refer to the Dropout Voltage parameter.

Not Reco

mmended

for N

ew D

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s:

SI-302

5KM

, SI-3

050K

M

SI-3000KM

6

2-2-3 Electrical Characteristics(1) （SI-3012KM,SI-3025KM,SI-3033KM） Ta = 25°C

Parameter Symbol

Ratings

Units SI-3012KM(Vo adjustable) SI-3025KM SI-3033KM

min typ max min typ max min typ max

Input

Voltage

VIN 2.4*1 *1 *1 V

Output

Voltage

Settings

VO

(Vadj) (1.24) (1.28) (1.32) 2.45 2.5 2.55 3.234 3.300 3.366

V Conditio

ns VIN=3.3V,Io=10mA VIN=3.3V,Io=10mA VIN=5V,Io=10mA

Line

Regulation

⊿VOLINE 15 15 15

mV Conditio

ns VIN=3.3 to 8V,

Io=10mA(Vo=2.5V) VIN=3.3V,Io=10mA VIN=3.3V,Io=10mA

Load

Regulation

⊿VOLOAD 40 40 40

mV Conditio

ns VIN=3.3V, Io=0 to

1A(Vo=2.5V) VIN=3.3V, Io=0 to 1A VIN=5V, Io=0 to 1A

Dropout

Voltage

VDIF1 0.4 0.4 0.4

V

Conditio

ns Io=0.5A(Vo=2.5V) Io=0.5A Io=0.5A

VDIF2 0.6 0.6 0.6 Conditio

ns Io=1A(Vo=2.5V) Io=1A Io=1A

Quiescent

Circuit

Current

Iq 350 350 350

μA Conditio

ns

VIN=3.3V,Io=0A,VC=2V,

R2=24kΩ VIN=3.3V,Io=0A,VC=2V VIN=5V,Io=0A,VC=2V

Circuit

Current at

Output OFF

Iq(OFF) 1 1 1

μA Conditio

ns VIN=3.3V,VC=0V VIN=3.3V,VC=0V VIN=5V,VC=0V

Temperature

Coefficient

of Output

Voltage

⊿Vo/

⊿Ta ±0.3 ±0.3 ±0.3

mV/℃ Conditio

ns Tj=0 to 100℃(Vo=2.5V) Tj=0 to 100℃ Tj=0 to 100℃

Ripple

Rejection

RREJ 55 55 55

dB Conditio

ns

VIN=3.3V,f=100 to

120Hz,Vo=2.5V VIN=3.3V,f=100 to 120Hz VIN=5V,f=100 to 120Hz

Overcurrent

Protection

Starting

Current*2

IS1 1.1 1.1 1.1

A Conditio

ns VIN=3.3V VIN=3.3V VIN=5V

VC Termin

al

Control

Voltage

(Output

ON)*3 VC,IH 2.2 2.2 2.2

V Control

Voltage

(Output

OFF) VC,IL 0.8 0.8 0.8

Control

Current

(Output

ON)

IC,IH 40 40 40

μA

Conditio

ns VC=2V VC=2V VC=2V Control

Current

(Output

OFF)

IC,IL -5 0 -5 0 -5 0 Conditio

ns VC=0V VC=0V VC=0V

*1: Refer to the clause of a difference in input and output voltage.

*2: Is1 is specified at the 5% drop point of output voltage Vo on the condition that VIN = overcurrent

protection starting current, Io = 10mA.

*3: Output is OFF when the output control terminal Vc is open. Each input level is equivalent to LS-TTL

level. Therefore, the device can be driven directly by LS-TTLs.

Attention … As PD=(VIN－Vo)×Io, VIN(MAX) and Io(MAX) must be referred to the data of P17, copper area vs power

dissipation upon actual applications.

Not Reco

mmended

for N

ew D

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s:

SI-302

5KM

, SI-3

050K

M

SI-3000KM

7

2-2-3 Electrical Characteristics(2) （SI-3010KM,SI-3050KM,SI-3090KM） Ta = 25°C

Parameter Symbol

Ratings

Units SI-3010KM(Vo adjustable) SI-3050KM SI-3090KM

min typ max min typ max min typ max

Input

Voltage

VIN 2.4*1 *1 *1 V

Output

Voltage

Settings

VO or

(Vadj) (0.98) (1.00) (1.02) 4.90 5.00 5.10 8.82 9.00 9.18

V Conditio

ns VIN=7V,Io=10mA VIN=7V,Io=10mA VIN=11V,Io=10mA

Line

Regulation

⊿VOLINE 30 75 54

mV Conditio

ns VIN=6 to 11V,

Io=10mA(Vo=5V) VIN=6 to 11V,Io=10mA VIN=10 to 15V,Io=10mA

Load

Regulation

⊿VOLOAD 75 40 40

mV Conditio

ns VIN=7V, Io=0 to 1A(Vo=5V) VIN=7V, Io=0 to 1A VIN=11V, Io=0 to 1A

Dropout

Voltage

VDIF1 0.3 0.3 0.3

V

Conditio

ns Io=0.5A(Vo=5V) Io=0.5A Io=0.5A

VDIF2 0.6 0.6 0.6 Conditio

ns Io=1A(Vo=5V) Io=1A Io=1A

Quiescent

Circuit

Current

Iq 600 600 600

μA Conditio

ns

VIN=7V,Io=0A,VC=2V,

R2=10kΩ VIN=7V,Io=0A,VC=2V VIN=11,Io=0A,VC=2V

Circuit

Current at

Output OFF

Iq(OFF) 1 1 1

μA Conditio

ns VIN=7V,VC=0V VIN=7V,VC=0V VIN=11V,VC=0V

Temperature

Coefficient

of Output

Voltage

⊿Vo/

⊿Ta ±0.5 ±0.5 ±1.0

mV/℃ Conditio

ns Tj=0 to 100℃(Vo=5V) Tj=0 to 100℃ Tj=0 to 100℃

Ripple

Rejection

RREJ 75 75 68

dB Conditio

ns

VIN=7V,f=100 to

120Hz,Vo=5V VIN=7V,f=100 to 120Hz VIN=11V,f=100 to 120Hz

Overcurrent

Protection

Starting

Current*2

IS1 1.1 1.1 1.1

A Conditio

ns VIN=7V VIN=7V VIN=11V

VC Termin

al

Control

Voltage

(Output

ON)*3 VC,IH 2.0 2.0 2.0

V Control

Voltage

(Output

OFF) VC,IL 0.8 0.8 0.8

Control

Current

(Output

ON)

IC,IH 40 40 40

μA

Conditio

ns VC=2V VC=2V VC=2V Control

Current

(Output

OFF)

IC,IL -5 0 -5 0 -5 0 Conditio

ns VC=0V VC=0V VC=0V

Input

Overvoltage

Shutdown

Voltage

VOVP 33 26 30

V Conditio

ns Io=10mA Io=10mA Io=10mA

*1: Refer to the clause of a difference in input and output voltage.

*2: Is1 is specified at the 5% drop point of output voltage Vo on the condition that VIN = overcurrent protection

starting current, Io = 10mA.

*3: Output is OFF when the output control terminal Vc is open. Each input level is equivalent to LS-TTL level.

Therefore, the device can be driven directly by LS-TTLs.

Attention …

SI-3010KM,SI-3050KM,SI-3090KM cannot be used in the following applications because the built-in

foldback-type overcurrent protection may cause errors during start-up stage;

Not Reco

mmended

for N

ew D

esign

s:

SI-302

5KM

, SI-3

050K

M

SI-3000KM

8

(1) Constant current load (2) Positive and negative power supply (3) Series-connected power supply (4) Vo

adjustment by raising ground voltage

As PD=(VIN－Vo)×Io, VIN(MAX) and Io(MAX) must be referred to the data of P17, copper area vs power

dissipation upon actual applications.

2-2-3 Electrical Characteristics(3) （SI-3120KM） Ta = 25°C

Parameter Symbol

Ratings Units

SI-3120KM

min typ max

Input

Voltage

VIN *1 V

Output

Voltage

Settings

VO or

(Vadj) 11.76 12.00 12.24

V Conditio

ns VIN=7V,Io=10mA

Line

Regulation

⊿VOLINE 72

mV Conditio

ns VIN=13 to 18V,

Io=10mA

Load

Regulation

⊿VOLOAD 180

mV Conditio

ns VIN=14V, Io=0 to 1A

Dropout

Voltage

VDIF1 0.3

V

Conditio

ns Io=0.5A

VDIF2 0.6 Conditio

ns Io=1A

Quiescent

Circuit

Current

Iq 600

μA Conditio

ns VIN=14V,Io=0A,VC=2V,

Circuit

Current at

Output OFF

Iq(OFF) 1

μA Conditio

ns VIN=7V,VC=0V

Temperature

Coefficient

of Output

Voltage

⊿Vo/

⊿Ta ±1.5

mV/℃ Conditio

ns Tj=0 to 100℃

Ripple

Rejection

RREJ 66 dB Conditio

ns VIN=14V,f=100 to 120Hz

Overcurrent

Protection

Starting

Current*2

IS1 1.1

A Conditio

ns VIN=14V

VC Termin

al

Control

Voltage

(Output

ON)*3 VC,IH 2.0

V Control

Voltage

(Output

OFF) VC,IL 0.8

Control

Current

(Output

ON)

IC,IH 40

μA

Conditio

ns VC=2V Control

Current

(Output

OFF)

IC,IL -5 0 Conditio

ns VC=0V

Input

Overvoltage

Shutdown

Voltage

VOVP 33

V Conditio

ns Io=10mA

*1: Refer to the clause of a difference in input and output voltage.

*2: Is1 is specified at the 5% drop point of output voltage Vo on the condition that VIN = overcurrent protection

starting current, Io = 10mA.

*3: Output is OFF when the output control terminal Vc is open. Each input level is equivalent to LS-TTL level.

Therefore, the device can be driven directly by LS-TTLs.

Not Reco

mmended

for N

ew D

esign

s:

SI-302

5KM

, SI-3

050K

M

SI-3000KM

9

Attention …

SI-3120KM cannot be used in the following applications because the built-in foldback-type overcurrent

protection may cause errors during start-up stage;

(1) Constant current load (2) Positive and negative power supply (3) Series-connected power supply (4) Vo

adjustment by raising ground voltage As PD=(VIN－Vo)×Io, VIN(MAX) and Io(MAX) must be referred to the data of P17, copper area vs power

dissipation upon actual applications.

Not Reco

mmended

for N

ew D

esign

s:

SI-302

5KM

, SI-3

050K

M

SI-3000KM

10

● 2-3 Circuit Diagram

2-3-1 Block Diagram

（SI-3010KM,SI-3012KM） （SI-3025KM,SI-3033KM,SI-3050KM,SI-3090KM,SI-3120KM）

2-3-2 Typical Connection Diagram

（SI-3010KM,SI-3012KM）

（SI-3025KM,SI-3033KM,SI-3050KM,SI-3090KM,SI-3120KM）

*1 For SI-3012KM,SI-3025KM,SI-3033KM.

It is the setup to use a ultra-low ESR capacitor such as a ceramics-capacitor for Co with these models.

When an electrolytic-capacitor is used for Co, they may oscillate at low-temperature.

*1 For SI-3010KM,SI-3050KM,SI-3090KM,SI-3120KM.

As for these models,they may oscillate when a ultra-low ESR capacitor such as ceramic-capacitor is used for Co.

Lo

ad

Lo

ad

Not Reco

mmended

for N

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s:

SI-302

5KM

, SI-3

050K

M

SI-3000KM

11

*2: D1: Reverse biased protection diodes

In the case of reverse bias between input and output, this diode will be required.

(Recommended diodes: SJPL-H2 made by Sanken)

It is unnecessary in case of Vo≦3.3V.

R1, R2: resistors for setting output voltages

Output voltages can be adjusted by connecting R1 and R2 as shown in the above figure.

R2: 10kΩ is recommended.(In case of the SI-3120KM,24kΩ is recommended.)

R1=(Vo-VADJ) /（VADJ /R2）

*3: In the case that Vo ≦ 1.5V is set, R3 should be inserted. 10kΩ is recommended for R3.

Regardless of the setup voltage, R3 is unnecessary in case of the SI-3012KM.

Not Reco

mmended

for N

ew D

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s:

SI-302

5KM

, SI-3

050K

M

SI-3000KM

12

● 3-1 Voltage Control In the SI-3000KM series, the driving circuit is controlled by comparing the reference voltage with the ADJ

terminal voltage (voltage divided by Vo detection resistor in fixed output products) to stabilize the output

voltage by varying the voltage between the emitter and collector of a main PNP power transistor. The

product of voltage between emitter and collector and the output current at this moment is consumed as heat.

● 3-2 Overcurrent Protection

3-2-1 Overcurrent Protection Characterization for

SI-3012KM,SI-3025KM,SI-3033KM The Drooping type overcurrent protection function is provided in these models. In the case of the series

regulator, as the output voltage drops subject to the overcurrent protection, the difference of input/output

voltages increases to cause significant heating. Special care should be taken for the current limiting type

overcurrent protection, since large current flows continuously.

3-2-2 Overcurrent Protection Characterization for

SI-3010KM,SI-3050KM,SI-3090KM,SI-3120KM The foldback type overcurrent protection function is provided in these models. After operation of the

overcurrent protection function, if the load resistance decreases and the output voltage drops, the output

current of products is squeezed to reduce the increase of loss. However, in the case of the foldback type

overcurrent protection function, since current limiting is also made at start-up, the function may not be used

for the following applications, as it may cause a start-up error.

(1) Constant current loads

(2) Plus/minus power supply

(3) DC power supply

(4) Output voltage adjustment by grounding-up

3. Operational Description

<Example of Drooping type overcurrent protection characteristic>

Output Voltage

Output Current

出力電圧

出力電流

< Example of Foldback Overcurrent Protection>

Output voltage

Output Current

Not Reco

mmended

for N

ew D

esign

s:

SI-302

5KM

, SI-3

050K

M

SI-3000KM

13

● 3-3 Thermal Shutdown

This IC is provided with the overheat protection circuit which detects the semiconductor junction

temperature of the IC to limit the driving current, when the junction temperature exceeds the set value

(around 150°C). Since the minimum operating temperature of the overheat protection circuit is 130°C, the

thermal design of Tj <125°C is required. Since the overheat protection has no hysteresis, as soon as the

overload state is released and Tj falls below the set temperature, the normal operation is automatically

restored. When the overheat protection function is operated in the overload state, the output voltage falls,

but at the same time the output current is decreased and in the consequence, overheat protection operation

and automatic restoration are repeated in a short interval, resulting eventually in the waveforms of output

voltage oscillation.

*Note for thermal shutdown characteristic

This circuit protects the IC against overheat resulting from the instantaneous short circuit, but it should

be noted that this function does not assure the operation including reliability in the state that overheat

continues due to long time short circuit.

出力電圧

ｼﾞｬﾝｸｼｮﾝ温度

<Example of Thermal Shutdown> Output voltage

Junction Temperature

Not Reco

mmended

for N

ew D

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s:

SI-302

5KM

, SI-3

050K

M

SI-3000KM

14

● 4-1 External Components

4-1-1 Input Capacitor CIN

The input capacitor is required to eliminate noise and stabilize the operation and values of 0.47μF - 22μF

are recommended. Any of ceramic capacitors or electrolytic ones may be used for the input capacitor.

4-1-2 Output Capacitor Co Co for SI-3010KM,SI-3050KM,SI-3090KM,SI-3120KM

In the output capacitor Co, larger capacitance than the recommended value is required for phase

compensation. Equivalent series resistance values (ESR) of capacitors are limited, and depending on

products, therefore the type of recommended capacitors is limited.

Recommended ESR values for SI-3010KM,SI-3050KM,SI-3090KM,SI-3120KM: 2Ω > ESR > 0.2Ω

It is recommended to use electrolytic capacitors. When capacitors with ultra-low ESR such as ceramic

capacitors, functional polymer capacitors,OS-capacitors etc., are used, phase margin is decreased, possibly

causing the oscillation of output voltage. Therefore these capacitors can not be used.

Co for SI-3012KM,SI-3025KM,SI-3033KM

Using a ceramics capacitor and a function polymer capacitor, OS-capacitor etc., is recommended.

As for these models,when a big-ESR capacitor such as electrolytic-capacitors was used, phase margin is

decreased and possibly causing the oscillation of output voltage. ESR's increase in the low temperature condition.

Therefore,

an electrolytic-capacitor can't be recommended because output may oscillate at a low temperature even when the

output doesn't oscillate at a room temperature.

4-1-3 Reverse bias protection diode D1 In the case of falling-down of the input voltage, it is recommended to insert a protection diode D1 against

the reverse bias between input and output. However, in the case of setting the Vout < 3.3V or lower, D1 is

not required including the case of reverse bias. In order to select a suitable D1, it should be taken into

consideration that the diode has adequate forward current withstand voltage against the instantaneous

discharge of energy stored in output capacitor Co.

The permissible value of the forward current per unit time of diode is specified in IFSM (A) and in the case

of our diode, it is specified at 50Hz half wave (10ms), but it should be noted that different companies may

specify different times. The selection of diode should be made by converting the specified time into the

actual discharging time so as to meet the required IFSM (A). The discharging time of Co is normally shorter

than 1ms, but it is recommended to do the conversion with 1ms in consideration of margin.

For conversion into IFSM, calculation should be made by using the equations (1) and (2).

XtI FSM

1

2

2

--- (1) As for IFSM, please refer to the catalog of each company.

t1 = specified time in catalog of each company

Converted IFSM＝2

2

t

X --- (2) t2: converted time (discharging time of Co)

4. Cautions

Not Reco

mmended

for N

ew D

esign

s:

SI-302

5KM

, SI-3

050K

M

SI-3000KM

15

<Graph 1>

Co　vs　Idis（放電電流）

0

20

40

60

80

100

120

1 10 100 1000

Co　uF

Idis　A

On the assumption of Cout = 470μF, IFSM of around 90A or more (in 1ms time period) is required and

according to our specifications of diode, IFSM is specified for 10ms, therefore the diode of 30A has the

tolerated dose of 94.8A (in 1ms) to prove that it is usable.

● 4-2 Pattern Design Notes

4-2-1 Input / Output Capacitor The input capacitor C1 and the output capacitor C2 should be connected to the IC as close as possible. If

the rectifying capacitor for AC rectifier circuit is on the input side, it can be used as an input capacitor.

However, if it is no close to the IC, the input capacitor should be connected in addition to the rectifying

capacitor.

4-2-2 ADJ Terminal (Output Voltage Set-up for SI-3010KM & SI-3012KM) The ADJ terminal is a feedback detection terminal for controlling the output voltage. The output voltage

set-up is achieved by connecting R1 and R2.

SI-3010KM: it should be set in a manner that IADJ is around 100μA.

SI-3012KM: it should be set in a manner that IADJ is around 50μA.

R1, R2 and output voltage can be obtained by the following equations:

IADJ=VADJ/R2 *VADJ = 1. 0V ± 2% (SI-3010KM), R2 = 10kΩ recommended

*VADJ = 1. 28V ± 3% (SI-3012KM), R2 = 24kΩ recommended

R1 = (Vo-VADJ) / IADJ R2 = VADJ / IADJ

Vout = R1× (VADJ / R2) + VADJ

Reference Charge at 5V Co vs. Idis (discharge current)

Not Reco

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● 5-1 Output ON / OFF Control

The ON/OFF control of output can be made by directly applying voltage to No. 1 Vc terminal. When the

Vc terminal is open, the operation is in OFF. The Vc terminal is in OFF below 0.8V and in ON at above

2V.

● 5-2 Thermal Design

5-2-1 Calculation of heat dissipation Heat generation of the surface mounting IC is generally dependent on size, material and copper foil area of

the mounted printed circuit board. Full attention should be paid to heat dissipation and adequate margin be

taken into consideration at thermal design. In order to enhance the heat dissipation effect, it is

recommended to enlarge the copper foil area connected to the stem part on the back side of the product.

The copper foil area of the printed circuit board significantly affects the heat dissipation effect.

As the junction temperature Tj (MAX) is an inherent value, it must be observed strictly. For

this purpose, heat sink design (thermal resistance of board) which is appropriate for Pd

(MAX) and Ta MAX is required. This is graphically shown in the heat derating curve for

easy understanding. The heat dissipation design is done in the following procedure.

1) The maximum ambient temperature in the set Ta MAX is obtained.

2) The maximum loss PdMAX which varies the input/output conditions is obtained.

Pd = (VIN - Vout) × Iout

3) The area of copper foil is determined from the intersection point in the heat derating

curve below shown.

5. Applications

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For reference information, the graph of copper foil area vs. thermal resistance between

junction temperature and ambient temperature θj-a and the graph of copper foil area vs.

permissible dissipation that both are in the single side copper foil board FR - 4 are shown

below.

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6.1 SI-3012KM

(Ta = 25°C) *Set Vout = 2.5V (R2 = 24kΩ)

6. Typical Characteristics

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6.1 SI-3010KM

(Ta = 25°C) *Set Vout = 5V (R2 = 10kΩ)

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Notice

・ The contents of this description are subject to change without prior notice for improvement etc.

Please make sure that any information to be used is the latest one.

・ Any example of operation or circuitry described in this application note is only for reference, and

we are not liable to any infringement of industrial property rights, intellectual property rights or

any other rights owned by third parties resulting from such examples.

・ In the event that you use any product described here in combination with other products, please

review the feasibility of combination at your responsibility.

・ Although we endeavor to improve the quality and reliability of our product, in the case of

semi-conductor components, defects or failures which occur at a certain rate of probability are

inevitable. The user should take into adequate consideration the safety design in the equipment or

the system in order to prevent accidents causing death or injury, fires, social harms etc..

・ Products described here are designed to be used in the general-purpose electronic equipment

(home appliances, office equipment, communication terminals, measuring equipment etc.). If

used in the equipment or system requiring super-high reliability (transport machinery and its

control equipment, traffic signal control equipment, disaster/crime prevention system, various

safety apparatus etc.), please consult with our sales office. Please do not use our product for the

equipment requiring ultrahigh reliability (aerospace equipment, atomic control, medical

equipment for life support etc.) without our written consent.

・ The products described here are not of radiation proof type.

・ The contents of this brochure shall not be transcribed nor copied without our written consent.

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